The present invention relates to a housing of a portable scanner which is moved on a surface of an original to capture an image thereof.
Conventionally, portable scanners which are moved on a surface of an original to capture a two-dimensional image of the original have been known. Generally, such a portable scanner is provided with a line image sensor extending in a longitudinal direction (i.e., a main scanning direction). The scanner is moved in a direction perpendicular to the longitudinal direction (i.e., an auxiliary scanning direction) so that a two dimensional image is scanned.
There are two types of portable scanners. One type of a scanner is provided with an image reading optical system (image forming optical system) for forming a real image on an image sensor. The other type of a scanner employs a contact type image sensor which does not have an image forming optical system.
The former type is relatively large since the optical system is included, and is relatively heavy. However, since the image reduction optical system is employed, even if an original is not completely planar, as far as the original is located within a depth of field, an in-focus image can be obtained. On the contrary, the latter type requires the original should contact the image reading surface of the sensor. However, in the latter type, the size of the scanner can be made compact since the image forming optical system is not necessary.
In view of portability, weight, size and cost, the latter type is preferable and, in fact, broadly used as the portable scanner.
Since the portable scanner employs the contact type image sensor, problems as described below arise.
When a page of a relatively thick book is to be scanned, if a page 90L of a thick book 90 is to be scanned, as shown in FIG. 9, since the other page 90R interferes with a longitudinal end side of an image sensor 1000 and prevents the image sensor 1000 from being positioned sufficiently close to a seam (i.e., the inner margin 90M side). If the image sensor 1000 is forcibly located closer to the seam of the book, then the page 90L to be scanned may form a curve and therefore, it becomes impossible to keep the scanner 1000 in contact with the page 90L of the book 90 completely.
It is therefore an object of the invention to provide a housing of a portable scanner which is capable of maintaining a page to be scanned flat, and positioned sufficiently close to the seam of a book.
For the above object, according to the present invention, there is provided a housing of a portable scanner, the housing having a planar image reading surface extending in a longitudinal direction of the housing, the image reading surface contacting an original to be scanned. Within at least one longitudinal end portion of the housing is formed such that a thickness, along a direction perpendicular to the image reading surface, is smaller at a position closer to the end of the housing, and is larger at a position farther from the end of the housing.
With the above structure, the side end portion of the housing does not interfere with lifted pages of a book. Thus, a page to be scanned remains flat, and the housing can be positioned sufficiently close to the seam of the book.
Optionally, an end of the image reading surface is located within the end portion. Thus, the end of the image reading surface can be located close to the seam of the book.
In particular, at least a part of a side surface at the end of the housing is formed to be inclined at an acute angle with respect to the image reading surface. The acute angle may be within a range of 30 degrees to 60 degrees, and preferably 45 degrees.
The inclined surface may include a planar surface. Alternatively, the inclined surface may include a curved surface which is curved at least in the longitudinal direction of the housing. In particular case, the curved surface may be a convex surface. Further alternatively, at least a longitudinal end portion of said housing is formed to have steps instead of the inclined surface.
Further optionally, a shape of the housing may be a rectangular parallelepiped.